So I'm getting some really bad gas mileage, so I picked up a OBDII reader and was looking at the O2 Sensor Data, the B1S1 and B2S1 sensors seem fine, and at idle the rear sensor seems ok too (although I'm new to all this, so sorry if I'm wrong) but when I give it some gas the rear sensor goes crazy. Is this normal? You'll see towards the end of the first pic I give it some gas.



Any help would be much appreciated.